San Francisco's return man from 2017 has been suspended for the first four games of the 2018 regular season for violating the league's policy on performance-enhancing substances, the team announced Friday.

"Unknowingly, I used a supplement that was on the NFL's banned substance list," Bolden said in a statement. "As a professional athlete, I take full responsibility for not verifying the ingredients of the supplement. In the future, I will be much better educated when choosing what to put in my body. It hurts to know that I will not be on the field with my team for the first four games of the season."

Bolden is eligible to return to the roster on Monday, Oct. 1, after the team's Week 4 tilt against the Chargers. In between, the 49ers also play the Lions in Week 2 and the Chiefs in Week 3.

Agent Michael Hoffman, who reps #49ers WR Victor Bolden, says Boldenâs positive drug test was because of âcontaminated creatine per NFLPAâs testing.â The drug policy is clear, but Hoffman says âin no way was Victor cheating. He will be pursuing legal remedies against the company"

The undrafted 23-year-old wideout signed a three-year, $1.66 million deal with the team last May. Bolden averaged 20.8 yards on 19 kick returns and just 5.8 yards off four punt returns.

A long shot to make the roster, Bolden can't afford a suspension on his record in San Francisco.

"Victor made an unintentional mistake, but learned a valuable lesson," 49ers general manager John Lynch said in a statement. "Professional athletes must be meticulous in their supplement choices. We know Victor is disappointed, but we hope this is a reminder to all our players how important it is to make educated decisions on what to put in their bodies."